FitnessGenes joins the fight against COVID-19
Tuesday, July 07, 2020. Author FitnessGenes
Tuesday, July 07, 2020. Author FitnessGenes
FitnessGenes are pleased to announce that we’ve launched one of the world’s first saliva tests for coronavirus (COVID-19).
Our antigen test detects whether or not you are currently carrying the SARS-CoV-2 virus that causes COVID-19 – all that’s required is a small, easily-obtained sample of saliva.
Based on test results, individuals can decide whether it’s necessary to self-isolate, trace contacts, and make changes to their workplace, thereby helping to prevent the spread of COVID-19.
Currently, most COVID-19 antigen tests are conducted using a deep nasopharyngeal swab. This involves inserting a long (about 6 inches) swab through the nostrils deep into the back of the throat. The swab is then rotated several times to obtain a nasal secretion which may or may not contain the SARS-CoV-2 virus.
Unsurprisingly, this technique often feels uncomfortable for the person being tested. Furthermore, it typically requires a trained healthcare professional to administer the test. As the insertion of a nasopharyngeal swab can trigger sneezing, the healthcare professional will also have to wear PPE (personal protective equipment) to avoid being infected.
By contrast, a saliva test avoids all of the above issues. As all you need to do is spit about 2 ml of saliva into a collection tube, saliva tests can be quickly done at home yourself, with minimum discomfort and without the need for trained personnel on hand.
Moreover, studies suggest that saliva tests have a comparable (if not better) ability to detect the SARS-CoV-2 virus compared to tests using nasopharyngeal swab samples.
The FitnessGenes COVID-19 saliva test is an antigen test – it assesses whether you are currently infected with the SARS-CoV-2 virus. You may have also heard these tests referred to as PCR tests.
Such tests detect the presence of genetic material, called RNA, that is specific to the SARS-CoV-2 virus. The RNA acts as a kind of molecular signature or hallmark of the virus. If you are currently infected with the virus (irrespective of whether you have symptoms), then you’ll shed viral particles containing the RNA signature into your saliva.
This RNA signature can then be detected using a laboratory process called RT-PCR (Reverse-Transcription Polymerase Chain Reaction).
As mentioned above, we use a procedure called RT-PCR to look for RNA that is specific to the SARS-CoV-2 virus. To fully understand the RT-PCR process, we need to more clearly explain what RNA is and how it's used by viruses.
Like human cells, viruses have genetic material that contains instructions for producing proteins. These proteins are essential for all the processes needed for the virus to survive. Rather gruesomely, this includes proteins needed to enter human cells, hijack human cellular machinery and enzymes, and then produce new virus copies.
Human genetic material is in the form of DNA (deoxyribonucleic acid) – a molecule with the characteristic “double-helix” shape formed of two strands joined to one another.
By contrast, the SARS-CoV-2 virus has its genetic material in the form of RNA (ribonucleic acid), a molecule which is formed of just one strand. Nevertheless, RNA still contains all the information needed to produce viral proteins.
When the SARS-CoV-2 virus infects us, it first attaches to the surface membranes of our cells by binding to receptors. The virus then enters inside and releases its RNA. The virus then hijacks human cellular machinery to replicate its own RNA, convert the RNA into new viral proteins, and then assemble new virus particles.
For example, as shown in the diagram below, the virus uses human cell organelles such as the endoplasmic reticulum (ER) and Golgi to produce new viral proteins and construct new virus particles (or virions).
Once formed, these new virus particles leave the cell and go on to infect other cells and further replicate.
Two particular proteins produced by the SARS-CoV-2 virus include the nucleocapsid (N) protein and the envelope (E) protein. The N protein helps to enclose the genetic material (in the form of RNA) of the virus and also takes part in replicating viral RNA. The E protein helps to form the viral envelope that surrounds and protects the whole virus particle. It plays a key role in the assembly of new virus particles.
The genes for the N and E proteins, which are contained within the viral RNA, are coded for, respectively, by the N and E genes.
The overarching aim of the FitnessGenes RT-PCR test is to detect whether your saliva sample contains these viral N and E genes.
During RT-PCR, we use special enzymes to first convert all of the viral RNA into a form of DNA known as complementary DNA (cDNA). This conversion process is called reverse transcription (the ‘RT’ part of RT-PCR). Reverse transcription will create complementary DNA copies of viral genes, including the N and E genes.
We then introduce specially designed molecules (called primers) which only bind to the complementary DNA copies of the viral N and E genes. Primers are like the specific teeth / bittings of a key. They have a unique molecular sequence which is designed to only fit with the complementary DNA sequence of a particular gene – in this case the viral N and E genes (these different genes will require different primers). Interestingly, these primers were developed by scientists across the world as part of a global, collaborative effort to fight coronavirus.
In the second step of RT-PCR, we use another reaction called a polymerase chain reaction (PCR) to create millions of copies (or ‘amplify’) the N and E genes. The reason for this amplification step is so we have enough detectable genetic material. If we relied solely on the small amount of genetic material in your saliva sample, it would be extremely difficult to detect the N and E gene sequences.
We also add special fluorescent molecules (called probes) that bind to the amplified N and E genes. The fluorescent probes give off a light signal to show that your saliva contained the viral N and E genes, meaning that you were infected with SARS-CoV-2 when you provided your saliva.
If you are not carrying the SARS-CoV-2 virus, your saliva sample will not contain the viral N and E genes. Consequently, the primers and probes will not be able to bind to the complementary DNA versions of these genes and there won’t be a light signal.
RT-PCR can be difficult to get your head around, but we’ve found this video from the DNA Learning Center that explains it well.
For more information about our coronavirus saliva test kits, including details of how to order kits and answers to frequently asked questions, head over to the FitnessGenes COVID-19 page.
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